Need a Powder Actuated Fastener That Goes Thru Steel First and Then Wood. 2

[Ron247]

Does anyone know of a reliable powder actuated fastener that goes through the steel first and then nails into wood. We are trying to field attach upwards through a 3/16" thick angle leg into an upright 2x8 joist. It is easy to find the fasten through wood first and then into the steel but not the reverse. I have never had to do this before.

The attachment is to stabilize the joist and connect it to the primary steel support (a Channel). It will have about 50 lbs of lateral force on it max.

 

[Celt83]

If you are only going thru 3/16" material I'd go with the Simpson Strong-Drive TB screws instead of a PAF.
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[NorthCivil]

A problem like this sounds like it is right up the alley of a Hilti engineer

you will get great support from them in my experience

 

[Ron247]

I made a generic suggestion of using a self-drilling screw but so far they have said no. They were the one who said to use a powder actuated but I pointed out the materials are in reverse order of what I was familiar with. I do not think they are aware of how fast the newer technologies can be installed as compared to "the good ole days".

Celt83, if you are familiar with the Simpson TB, what is the purpose of the "wings" near the end of the fastener?

 

[Ron247]

NorthCivil, just got off the phone with Hilti and they did not have any powder products for steel to wood but did have for wood to steel.

 

[Celt83]

The "wings" are the self tapping bit to cut thru the steel, so you'd probably want a fastener length to give you proper penetration neglecting the "wings" dimension.

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https://github.com/buddyd16/Structural-Engineering

 

[GC_Hopi]

Are you able to bolt to the side of the joist or predrill the steel then screw into the wood? A hanger bracket? Just throwing some idea out there

 

[Agent666]

I'm just curious (if you know) what there issue was with some predrilled countersunk holes in the angle and some screws? Surely firing a PAF on site takes about 3 times longer than a monkey screwing in a screw with an impact driver.

 

[Agent666]

Those wings in the link to Simpson screws are actually for the wood, because usually they are used for drilling through the wood first (they break off when you hit the metal) . They'll only go through a certain thickness of metal (cold formed purlin ok, but hot rolled steel over 3-5mm maybe not depending on thickness) before you need to predrill the steel, then you have obvious issues with lining things up.

Do you have access to the far side of the wood to drill through the wood into the angle?

 

[hokie66]

I doubt it can be done. You need to predrill the steel and use appropriate screws.

If you want to persist with this idea, you should contact a fastener supplier. If they do recommend a fastener, I would do a trial myself. It is not always as practical as described.

 

[Celt83]

Agent is right on the wings for some reason I read wings and thought you were asking about the self tapping tip.

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https://github.com/buddyd16/Structural-Engineering

 

[KootK]

X2 for can't be done. I almost feel that such an anchor would be contrary to the technology itself. As I understand it, the projectile pretty much friction welds itself into the substrate when that substrate is hot rolled steel. It seems like a lot to ask to have the pin punch through the steel and still retain enough velocity and tip blade integrity to engage the wood. Granted, 3/16" is pretty close to being gauge material.

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[DBronson]

Ron:

If I understand your situation the pins are loaded in shear. If that's so, PAF's would work fine provided the installers drilled a pilot hole in the steel first (as noted above). Some experimentation would be needed to find the minimum diameter hole size that allows the pin to seat itself fully. The trick would be to get the pin centered on the hole, but often the pin tip projects a bit from the "gun".

Another option would be to use a pneumatic nailer for metal connectors. Link These tools are designed to install nails for joist hangers etc. Again, a shank hole would be required to be drilled in the steel first.

A third option is to drill a shank hole in the steel and drive a PK nail. A framing carpenter with a 22 oz. hammer could drive those with only one or two blows - it'd go pretty fast.

As others have noted above, there probably isn't any solution that avoids drilling the steel. However, in our experience the self-drilling fasteners are pretty slow. With the proper bits a pilot or shank hole should only take 5-6 seconds.

Regards,

DB

 

[civeng80]

These are very dangerous tools. I used one many years ago where the pin penetrated the steel and broke in half the other piece shot right through the steel and went though a window about 20m away like a rifle. I would recommend screw fixing.

 

[XR250]

Pre-drill and bolt or screw. A sharp bit will go thru 3/16" material in 30 seconds max.

 

[Ron247]

Thanks all, it sounds like what I am asking for is a unicorn. Just wanted to run the idea past this group since the architect thinks it exists. I had pointed out to him that I did not think it did exist. I am going to tell them it does not exist and we either drill holes or use a self-drilling fastener. Most of the self-drillers appear to be through wood and then into steel the steel.

The fastener is only to prevent lateral movement in any direction.

 

[jayrod12]

I don't think there are self drilling fasteners that do steel to wood, so they should just drill holes and then install standard wood screws.

 

[IRstuff]

I don't see why self-drilling metal screws can't do wood under metal, provided they're not too large a diameter, like #6 or #8.

I just installed some metal closet rods with self-drilling screws, and I drilled and drilled for a while thinking that the point must have gotten dull, and then it finally got through. Having the target fixed will allow a bit more longitudinal force. Those same screws go into wood very well.

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[jayrod12]

I fear that the self drilling portion will mangle the hole in the wood too much to be significantly useful.

 

[BridgeSmith]

IRstuff, A closet rod is typically much thinner and softer metal than a 3/16" rolled angle. A self drilling fastener in a 3/16" structural angle will 1) drill a hole in the wood, eliminating most of the tension capacity in the wood, 2) have mostly flattened threads by the time it cuts threads in the steel, further reducing its grip on the wood, and 3) will be threaded into the steel, making it impossible to tighten in the wood, unless you completely strip the threads in the steel, which in my experience doesn't happen - the screw snaps instead.

If only shear strength is required, just drill holes in the steel and drive nails. If tension capacity is required, drill holes and drive screws.